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PubMed1991

Using Q-Probes to improve the quality of laboratory medicine: a quality improvement program of the College of American Pathologists.

This paper will review the reasons for the increasing emphasis on quality assurance in American healthcare and laboratory medicine. This emphasis is driven in part by economic, social and regulatory concerns as well as the traditional commitment to the search for excellence in services provided to patients. The Q-Probes Program of the College of American Pathologists (CAP) represents a response to these pressures and will be described in some detail. The program is based upon the historical success of interlaboratory comparison programs developed and sponsored by the CAP in achieving demonstrable improvement in laboratory performance. These programs are dependent on the gathering of data from large numbers of laboratories in order to establish provisional "benchmarks" of quality practice which serve as a baseline for systematic quality improvement efforts. The Q-Probes Program gathers peer-group specific institutional data concerning defined aspects of quality practice in pathology and laboratory medicine. These highly structured programs provide laboratories and pathology services with a format to collect data for submission to the CAP for analysis and to compare their performance against that of appropriately stratified peer groups. Several representative examples chosen from clinical laboratory medicine and pathology will be presented. We will attempt to demonstrate how individual laboratory and pathology services utilize aggregate data to effect specific changes in practice that lead to improvement in processes of patient care and better patient outcomes.

Blood Specimen Collection↗

PubMed2004

Aspirin in cardiovascular disorders. What is the optimum dose?

Clinical trials of aspirin (acetylsalicylic acid) for cardiovascular disorders have employed doses defined for other pharmacological effects of the drug (such as analgesic effects). Antioxidant and anti-inflammatory mechanisms with different dose-response relationships may contribute to the clinical effect of aspirin in cardiovascular disease. The optimal aspirin dose remains uncertain. Although the difference between 325 mg/day and 81 mg/day of aspirin sounds trivial, finding an optimal aspirin dose has enormous potential to reduce ischemic events. Large aspirin doses have not been associated with proportionally greater benefit. For patients with ischemic heart disease, overall consensus defines a range between 75 and 160 mg/day for the secondary prevention of myocardial infarction, stroke, and vascular death. Any benefit of aspirin must be measured against its adverse effects, principally gastrointestinal hemorrhage. The potential for adverse bleeding events may be lower with a 81mg dose, while maintaining clinical benefit. Although current aggregate data is reassuring about aspirin administration, it is increasingly clear that existing aspirin studies are insufficient to conclusively determine an optimal aspirin dose. Platelets can be activated by pathways that are not blocked by aspirin, and the dose of aspirin needed to fully suppress platelet aggregation may be higher in some patients as a result. Higher doses of aspirin than are currently used (75-325 mg/day) may be required in these patients to achieve desired antithrombotic effects. Better understanding of aspirin-resistant populations will facilitate identification of patients who require higher aspirin doses or alternative forms of antiplatelet therapy.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2005

Influence of mechanical stress and surface interaction on the aggregation of Aspergillus niger conidia.

Productivity of fungal cultures is closely linked with their morphologic development. Morphogenesis of coagulating filamentous fungi, like Aspergillus niger, starts with aggregation of conidia, also denominated as spores. Several parameters are presumed to control this event, but little is known about their mode of action. Rational process optimization requires models that mirror the underlying reaction mechanisms. An approach in this regard is suggested and supported by experimental data. Aggregation kinetics was examined for the first 15 h of cultivation under different cultivation conditions. Mechanical stress was considered as well as pH-dependent surface interaction. Deliberations were based on a two-step aggregation mechanism. The first aggregation step is only affected by the pH-value, not by the fluid dynamic conditions in the bioreactor. The second aggregation step, in contrast, depends on the pH-value as well as on agitation and aeration induced power input. For the given experimental set-up, agitation had much more influence than aeration. In addition, hyphal growth rate was determined to be the driving force for the second aggregation step.

Aspergillus niger↗

PubMed1999

Cohort analysis of cigarette smoking and lung cancer incidence among Norwegian women.

BACKGROUND: Cancer registries have for decades surveyed the development of cancer diseases. Data on incident cases includes demographic variables. Knowledge of the temporal distribution of risk factors on the same variables makes it possible to model the relationship between disease and risk factor. The results of such analyses might be difficult to interpret since they are based on aggregated data. But the availability of these data sources should encourage further exploration of its possibilities and limitations. METHODS: The temporal pattern of smoking habits in 5-year birth cohorts from 1890-1949 was established, with data on the proportions of current smokers, former smokers and non-smokers and estimated average daily consumption of tobacco and average duration of smoking. The lung cancer incidence among the cohorts in 1953-1992 was analysed by a model which included an additive excess risk for smokers that depended on daily dose and duration of smoking. RESULTS: The lung cancer incidence in later decades was adequately described by the model, which showed a simple relationship with smoking behaviour in the cohorts. For both current smokers and former smokers, the excess risk was about proportional to the daily amount smoked and the 4.5 power of duration of smoking. The age-specific rates for non-smokers were close to a fifth-power curve of age. CONCLUSIONS: Even if lung cancer incidence is not determined separately for groups with known smoking habits, plausible estimates of the effect of smoking can be derived if appropriate information is available on temporal smoking habits in the population.

Adult↗

PubMed2003

Heterogeneity within the Asian American community.

BACKGROUND: Educational interventions are grounded on scientific data and assumptions about the community to be served. While the Pan Asian community is composed of multiple, ethnic subgroups, it is often treated as a single group for which one health promotion program will be applicable for all of its cultural subgroups. Compounding this stereotypical view of the Pan Asian community, there is sparse data about the cultural subgroups' similarities and dissimilarities. The Asian Grocery Store based cancer education program evaluation data provided an opportunity to compare data collected under identical circumstances from members of six Asian American cultural groups. METHODS: A convenience sample of 1,202 Asian American women evaluated the cultural alignment of a cancer education program, completing baseline and follow-up surveys that included questions about their breast cancer knowledge, attitudes, and screening behaviors. Participants took part in a brief education program that facilitated adherence to recommended screening guidelines. RESULTS: Unique recruitment methods were needed to attract participants from each ethnic group. Impressions gained from the aggregate data revealed different insights than the disaggregate data. Statistically significant variations existed among the subgroups' breast cancer knowledge, attitudes, and screening behaviors that could contribute to health disparities among the subgroups and within the aggregate Pan Asian community. CONCLUSION: Health promotion efforts of providers, educators, and policy makers can be enhanced if cultural differences are identified and taken into account when developing strategies to reduce health disparities and promote health equity.

Journal Article↗

PubMed2005

A novel computer based expert decision making model for prostate cancer disease management.

PURPOSE: We propose a strategic, computer based, prostate cancer decision making model based on the analytic hierarchy process. We developed a model that improves physician-patient joint decision making and enhances the treatment selection process by making this critical decision rational and evidence based. MATERIALS AND METHODS: Two groups (patient and physician-expert) completed a clinical study comparing an initial disease management choice with the highest ranked option generated by the computer model. Participants made pairwise comparisons to derive priorities for the objectives and subobjectives related to the disease management decision. The weighted comparisons were then applied to treatment options to yield prioritized rank lists that reflect the likelihood that a given alternative will achieve the participant treatment goal. Aggregate data were evaluated by inconsistency ratio analysis and sensitivity analysis, which assessed the influence of individual objectives and subobjectives on the final rank list of treatment options. RESULTS: Inconsistency ratios less than 0.05 were reliably generated, indicating that judgments made within the model were mathematically rational. The aggregate prioritized list of treatment options was tabulated for the patient and physician groups with similar outcomes for the 2 groups. Analysis of the major defining objectives in the treatment selection decision demonstrated the same rank order for the patient and physician groups with cure, survival and quality of life being more important than controlling cancer, preventing major complications of treatment, preventing blood transfusion complications and limiting treatment cost. Analysis of subobjectives, including quality of life and sexual dysfunction, produced similar priority rankings for the patient and physician groups. Concordance between initial treatment choice and the highest weighted model option differed between the groups with the patient group having 59% concordance and the physician group having only 42% concordance. CONCLUSIONS: This study successfully validated the usefulness of a computer based prostate cancer management decision making model to produce individualized, rational, clinically appropriate disease management decisions without physician bias.

Brachytherapy↗

PubMed1993

Equitable access to health care: methodological extensions to the analysis of physician utilization in Canada.

In this paper we analyse the distribution of family physician use in Canada to explore whether the stated goal of reasonable access to care has been achieved. We test hypotheses to see whether (a) variations in incidence and quantity of use are independent of need for care as proxied by self-assessed health status and (b) any observed relationship between variations in use and need is independent of other population characteristics. Previous research has conceptual, statistical and data limitations which bring into question the validity of the findings. These limitations are addressed by using more appropriate data, a conditional model for service utilization and correction for self-selectivity of users in the statistical analysis. Variations in need are identified as important and significant in explaining variations in both incidence and quantity of use with the estimated relationship between use and need being positive. Other population characteristics were found to be important and significant in explaining variations in use although household income is not among them. The relationship between use and need is associated with other variables including education, social support and region of residence. These findings suggest that analyses of utilization based on simple multivariate techniques and aggregate data can produce a picture of utilization that conceals important, policy relevant relationships while revealing other relationships that are essentially artifacts of inappropriate aggregation in ways which provide a false sense of achievement.

Adolescent↗

PubMed2006

Changes in the seasonality of suicides over time in Slovenia, 1971 to 2002.

BACKGROUND: Recent studies have reported changes in the time patterns of suicide, with reduced seasonality in some European and Asian countries. Anyway conflicting data were reported on the fading of suicide seasonality, and in some countries a rising trend was reported. METHODS: Harmonic spectral analysis was used to analyze all suicides in Slovenia in the years 1971 to 2002 (14,325 among males; 4350 among females). Analyses of overall changes are based on data aggregated by intervals of 8 years. RESULTS: In both sexes, seasonal variance accounts for a statistically significant proportion of total variance (36.0% among males; 13.3% among females). Anyway in both sexes the season-attributable variance in the latest interval is considerably lower than in the preceding periods. LIMITATIONS: Data could not be analyzed according to age or to mental disorder diagnosis, since this information was not available. CONCLUSION: The seasonal effect on mortality by suicide is sensitive to change, but its causes seem not to be sex-dependant.

Female↗

PubMed2004

Issues influencing development of the Canadian Cardiovascular Information Network.

The 1995 Consensus Conference of the Canadian Cardiovascular Society on "Indications for and Access to Revascularization" recommended that Canadian centres with invasive cardiovascular facilities should participate in a national observational database that monitors the selection of patients, as well as evaluate outcomes. The Canadian Cardiovascular Society, the Heart and Stroke Foundation of Canada, and Health Canada with IBM as a partner, initiated a process to identify factors influencing the development of the Canadian Cardiovascular Information Network. IBM's "Business Discovery Methodology" was adapted for health care. Structured interviews with representatives of health organizations, cardiovascular databases and research institutes were conducted across Canada, followed by a workshop to identify goals, issues and challenges. Participants identified goals for a cardiovascular database (eg, evidence-based decision-making), project related issues (eg, respecting the integrity of existing databases) and health care related issues (eg, cardiac waiting lists). Challenges included initial mistrust between representatives of provincial cardiovascular databases and national agencies, and a lack of sustained funding. A Project Team was formed to address 'cardiac waiting lists'. Analysis of Alberta and Ontario data identified differences in definitions, such as when the waiting time for bypass surgery began, that impeded detailed comparisons. Development of a centralized national database was not feasible at this time for political, technical and financial reasons. However, provincial cardiovascular database representatives agreed to work together and to share aggregate data and analyses. A first step toward developing a national surveillance system for cardiovascular services will be achieving consensus about standardizing data definitions. This process will require sustained funding.

Canada↗

PubMed1993

Methodologic research needs in environmental epidemiology: data analysis.

A brief review is given of data analysis methods for the identification and quantification of associations between environmental exposures and health events of interest. Data analysis methods are outlined for each of the study designs mentioned, with an emphasis on topics in need of further research. Particularly noted are the need for improved methods for accommodating exposure assessment measurement errors in analytic epidemiologic studies and for improved methods for the conduct and analysis of aggregate data (ecologic) studies.

Data Interpretation, Statistical↗

PubMed2000

Trp1, a candidate protein for the store-operated Ca(2+) influx mechanism in salivary gland cells.

The trp gene family has been proposed to encode the store-operated Ca(2+) influx (SOC) channel(s). This study examines the role of Trp1 in the SOC mechanism of salivary gland cells. htrp1, htrp3, and Trp1 were detected in the human submandibular gland cell line (HSG). HSG cells stably transfected with htrp1alpha cDNA displayed (i) a higher level of Trp1, (ii) a 3-5-fold increase in SOC (thapsigargin-stimulated Ca(2+) influx), determined by [Ca(2+)](i) and Ca(2+)-activated K(+) channel current measurements, and (iii) similar basal Ca(2+) permeability, and inhibition of SOC by Gd(3+) but not by Zn(2+), as compared with control cells. Importantly, (i) transfection of HSG cells with antisense trp1alpha cDNA decreased endogenous Trp1 level and significantly attenuated SOC, and (ii) transfection of HSG cells with htrp3 cDNA did not increase SOC. These data demonstrate an association between Trp1 and SOC and strongly suggest that Trp1 is involved in this mechanism in HSG cells. Consistent with this suggestion, Trp1 was detected in the plasma membrane region, the proposed site of SOC, of acinar and ductal cells in intact rat submandibular glands. Based on these aggregate data, we propose Trp1 as a candidate protein for the SOC mechanism in salivary gland cells.

Animals↗

PubMed2000

Estimating transition probabilities from aggregate samples plus partial transition data.

Longitudinal studies often collect only aggregate data, which allows only inefficient transition probability estimates. Barring enormous aggregate samples, improving the efficiency of transition probability estimates seems to be impossible without additional partial-transition data. This paper discusses several sampling plans that collect data of both types, as well as a methodology that combines them into efficient estimates of transition probabilities. The method handles both fixed and time-dependent categorical covariates and requires no assumptions (e.g., time homogeneity, Markov) about the population evolution.

Acquired Immunodeficiency Syndrome↗

PubMed1985

Interaction between HeLa cells and adenovirus type 2 virions neutralized by different antisera.

Three adenovirus type 2-specified immunogens elicited neutralizing antibodies when injected into rabbits; these were the fiber, the hexon, and the penton base. Adenovirus type 2 virions, neutralized by antihexon- or anti-penton base antisera, attached to HeLa cells to the same extent as untreated control virus, and after attachment, neutralized viruses also became sensitive to DNase treatment. A fraction of 75 to 80% of the attached antibody-treated virions penetrated the plasma membrane, which should be compared with an 84 to 88% penetration level in the control series. A majority of the antihexon-neutralized virions was found in intracellular vesicles, as revealed with an electron microscope, but in the case of anti-penton base neutralization, a maximum of 50% of the virions was retained within vesicles, and ca. 30% was free in the cytoplasmic compartment. A value greater than 45% was never obtained for neutralization with a monospecific anti-penton base antiserum, which could imply the existence of alternative pathways for virus penetration into HeLa cells--one of these being sensitive to treatment with anti-penton base antiserum. Antisera containing antifiber specificities efficiently aggregated virions, and the aggregation data mirrored the degree of neutralization. Antifiber-neutralized virions attached to cells to a three- to five times greater extent than untreated control virus, but the former virions had a reduced ability to become sensitive to DNase treatment. Around 15% of the attached antifiber-treated virions was found as large aggregates inside multivesicular bodies or lysosomes.

Adenoviruses, Human↗

PubMed2006

Increased platelet aggregation in vivo in the Zucker Diabetic Fatty rat: differences from the streptozotocin diabetic rat.

BACKGROUND AND PURPOSE: Diabetes mellitus, especially type 2, is associated with increased arterial thrombosis. Our aims were (i) to characterize and compare platelet aggregation in vivo and in vitro in a type 2 diabetes model; and (ii) to determine whether these results differ from those in a type 1 diabetes model. EXPERIMENTAL APPROACH: Platelet aggregation to ADP in lean or obese Zucker Diabetic Fatty (ZDF) rats and in streptozotocin (STZ)-treated or control Wistar rats was measured in vitro, using Born aggregometry, and in vivo, by (111)Indium-labelled pulmonary platelet accumulation. KEY RESULTS: In vivo, ADP responses were higher in obese (type 2 model) than lean ZDF rats. However, in vitro, ADP aggregation did not differ between platelet-rich plasma from ZDF lean or obese rats; nor was any difference seen in ADP responses when platelets from either lean or obese ZDF rats were suspended in plasma from obese or lean ZDF rats, respectively. In vivo, ADP responses were similar in STZ treated (type 1 model) and control rats whereas, in vitro, isolated platelets from STZ diabetic rats were more responsive to ADP aggregation than controls. Platelets from control or STZ-treated rats suspended in plasma from STZ-treated rats exhibited reduced ADP aggregation, compared to when suspended in plasma from control rats. CONCLUSIONS AND IMPLICATIONS: The platelet aggregation results obtained in vitro do not reflect those in vivo, therefore in vitro aggregation data should be interpreted with caution. Moreover, both in vitro and in vivo, different diabetic models exhibit important differences in platelet responsiveness.

Animals↗

PubMed2005

Individual patient data meta-analysis : Cervical stitch (cerclage) for preventing pregnancy loss in women.

BACKGROUND: Cervical cerclage is a surgical procedure involving suturing the cervix with a purse type stitch to keep it closed during pregnancy. This procedure has been used widely in the management of pregnancies considered at high risk of preterm delivery. Several observational studies into the efficacy of cervical cerclage have claimed high rates of successful pregnancy outcome in women with a poor obstetric history attributed to cervical incompetence. However, a recent aggregate data Cochrane review found no such conclusive evidence from seven included randomised studies. Current data suggests that cervical cerclage is likely to benefit women considered to be 'at very high risk' of a second trimester miscarriage due to a cervical factor, however identifying such women remains elusive and many women may be treated unnecessarily. Undertaking an individual patient data (IPD) meta-analysis of the studies will allow us to investigate whether treatment is more effective in particular subgroups. Such an analysis will also provide a more powerful analysis of the predictors of preterm delivery and pregnancy loss, including ultrasound measurement of cervical length, and will allow a more complete analysis of 'time to event' outcomes. METHODS/DESIGN: The analysis will include data from randomised trials comparing the intervention of elective cerclage versus no cerclage or bedrest to prevent miscarriage or pre-term labour. A specific list of data will be requested for each trial, including demographic and obstetric history data. The primary outcomes of interest will be neonatal mortality/morbidity. Attention will also be given to secondary outcomes such as time from randomisation to delivery, preterm delivery before 32 weeks and maternal morbidity. An intention to treat analysis will be performed, with attention paid to assessing clinical and statistical heterogeneity. Multilevel models with patients and trials as the two levels will be explored to investigate treatment effect on various outcomes. Patient-level covariates will be incorporated into the models in an attempt to account for statistical heterogeneity as well as to investigate interactions with treatment effect. DISCUSSION: Predictive models generated from our analysis should lead to more effective counselling of women at risk and a more cost effective use of cerclage.

Journal Article↗

PubMed2001

Prophylaxis of oral mucositis in irradiated head-and-neck cancer patients: a proposed classification scheme of interventions and meta-analysis of randomized controlled trials.

PURPOSE: To identify, classify, and evaluate agents used in the prophylaxis of oral mucositis in irradiated head and neck cancer patients. METHODS: Data sources included multiple databases and manual citation review of relevant literature. Based on the eligibility criteria, 59 studies were independently reviewed by two reviewers. Forty-two studies were included in the classification scheme, of which 15 met the criteria for inclusion in the meta-analysis. Data were extracted by duplicate independent review, with disagreement resolved by consensus. RESULTS: Overall, the interventions reduced the odds of developing severe oral mucositis, when assessed by clinicians, by 36% (OR: 0.64; 95% CI: 0.46, 0.88). Subgroup analysis suggested that only the narrow-spectrum antibacterial lozenges were effective (OR: 0.45; 95% CI: 0.23, 0.86); however, the power of the aggregated data in the other classes may have been insufficient to detect differences. When the outcome was assessed by patients, no significant difference was seen in the outcome between the treatment and the control groups (OR: 0.79; 95% CI: 0.56-1.12). CONCLUSIONS: Overall, interventions chosen on a sound biologic basis to prevent severe oral mucositis are effective. In particular, when oral mucositis is assessed by clinicians, narrow-spectrum antibiotic lozenges appear to be beneficial. Methodologic limitations were evident in many of the studies. Further research using validated measurement tools in larger, methodologically sound trials is warranted.

Confidence Intervals↗

PubMed2006

Privacy protection versus cluster detection in spatial epidemiology.

OBJECTIVES: Patient data that includes precise locations can reveal patients' identities, whereas data aggregated into administrative regions may preserve privacy and confidentiality. We investigated the effect of varying degrees of address precision (exact latitude and longitude vs the center points of zip code or census tracts) on detection of spatial clusters of cases. METHODS: We simulated disease outbreaks by adding supplementary spatially clustered emergency department visits to authentic hospital emergency department syndromic surveillance data. We identified clusters with a spatial scan statistic and evaluated detection rate and accuracy. RESULTS: More clusters were identified, and clusters were more accurately detected, when exact locations were used. That is, these clusters contained at least half of the simulated points and involved few additional emergency department visits. These results were especially apparent when the synthetic clustered points crossed administrative boundaries and fell into multiple zip code or census tracts. CONCLUSIONS: The spatial cluster detection algorithm performed better when addresses were analyzed as exact locations than when they were analyzed as center points of zip code or census tracts, particularly when the clustered points crossed administrative boundaries. Use of precise addresses offers improved performance, but this practice must be weighed against privacy concerns in the establishment of public health data exchange policies.

Algorithms↗

PubMed2003

Three steps to data quality.

BACKGROUND: The quality of data in general practice clinical information systems varies enormously. This variability jeopardizes the proposed national strategy for an integrated care records service and the capacity of primary care organisations to respond coherently to the demands of clinical governance and the proposed quality-based general practice contract. This is apparent in the difficulty in automating the audit process and in comparing aggregated data from different practices. In an attempt to provide data of adequate quality to support such operational needs, increasing emphasis is being placed on the standardisation of data recording. OBJECTIVE: To develop a conceptual framework to facilitate the recording of standardised data within primary care. METHOD: A multiprofessional group of primary care members from the South Thames Research Network examined leading guidelines for best practice. Using the nominal group technique the group prioritized the information needs of primary care organisations for managing coronary heart disease according to current evidence. RESULTS: Information needs identified were prioritized and stratified into a functional framework. CONCLUSION: It has been possible within the context of a primary care research network to produce a framework for standardising data collection. Motivation of front-line clinicians was achieved through the incorporation of their views into the synthesis of the dataset.

Comorbidity↗